NAL Research Corporation (451-93156-002A)
11
The A3LA-RM accepts either +4.0V to +5.4V or +5.0V to +32V input. The A3LA-RM is shipped with
hardware set for +5.0V to +32V input. It can be changed to +4.0V to +5.4V input through an internal
jumper—POWER MUST BE DISCONNECTED BEFORE RESETING THE JUMPER. The jumper can be found by
removing the modem’s bottom plate. With the A3LA-RM held in the position shown in Figure 2 (DB25
connector to the left), the A3LA-RM is set for 4.0V to +5.4V when the red jumper is on the middle and left
pins and is set for +5.0V to +32V when the jumper is on the middle and right pins. Each pin is also labeled
with 5V and 32V to the left and right pins, respectively.
NOTE: User MUST remember the input voltage setting on the A3LA-RM and not to apply
voltage above the maximum limit (of either 5.4V or 32V). The A3LA-RM will be damaged
beyond repair with warranty voided if this were to occur.
IMPORTANT: User can remove the A3LA-RM’s bottom plate to set the jumper but not for
repair or services. The warranty is voided if the A3LA-RM is disassembled for any reason
other than to set the jumper.
3.4 Power On/Off Control
With the EXT_ON_OFF pin is left unconnected, the A3LA-RM will automatically turn on or off when
external DC power is applied or removed. Prior to turning the A3LA-RM off, command AT*P0 should be
issued to ensure all memory write activity is completed. When the A3LA-RM is powered off, its internal
power-on-reset circuit requires two seconds for voltages to decay. Users should not re-apply power until this
time has elapsed. If the two-second wait time is not adhered to, the reset circuit may not operate and the
A3LA-RM could be placed in a non-operational state. The state is not permanent and can be rectified by the
above procedure.
The A3LA-RM will automatically turn on/off when external DC power is applied/removed via the EXT_B+
and EXT_GND inputs. The EXT_ON_OFF (pin 1) control input is used to turn a powered A3LA-RM on and off
in a toggle fashion. The EXT_ON_OFF control input is normally “floating” (i.e. high). When it is pulled to GND
level (i.e. low) for at least 270 ms and released, the A3LA-RM will alternate from its current on/off state.
The current drawn on the external load used to pull the A3LA-RM to GND is no more than 0.5mA. The signal
on pin 1 is considered GND when it is at 0.5V or less.
Figure 2. Power Input Setting for the A3LA-RM.
Red jumper used
to set input
voltage range
